1. Technical Field
The present invention relates generally to an optical grating coupler, and in particular, to a subwavelength grating coupler for silicon integrated photonics.
2. Description of Related Art
Guided wave optical devices and systems are being utilized in many applications in the telecommunications, cable television, instrumentation and computation industries. A variety of devices have been developed and utilized in implementing the use of guided waves for communicating information. These devices include the use of fiber optic cables for transmitting optical signals over longer distances and higher bandwidths than many other forms of communication. These devices also include planar optical waveguides in which optical signals are confined to narrow channels on a roughly two dimensional surface such as a silicon chip where the optical signals are routed, split, filtered, multiplexed and demultiplexed, switched, sensed, etc. as guided waves. By utilizing planar optical waveguides on silicon chips or other similar materials, a tremendous amount of existing technology is available for the manufacturing of these devices.
Various types of couplers are utilized for transitioning optical signals from a fiber optic cable to a silicon chip surface waveguide including prism couplers and grating couplers. There are many varieties of these couplers with varying characteristics such as efficiency, bandwidth, and manufacturability.